Power over Ethernet (POE) powered devices (PDs) receive power and data from a power sourcing equipment (PSE) device through Ethernet cables. The Institute of Electrical and Electronics Engineers (IEEE) defined a collection of standards defining the physical layer and data link layer's media access control of wired Ethernet, which standards may be referred to as IEEE 802.3. The POE standards were defined as a subsection within the IEEE 802.3 standard. IEEE 802.3af standard defines a POE standard wherein the PSE device provides a maximum continuous power per cable of approximately 15.4 Watts. The IEEE 802.3at standard specifies that the PSE may provide a maximum continuous power output of approximately 25.5 Watts.
In operation, the PSE device may detect a maintain power signature (MPS) to determine if a PD is connected and continues to require power, in accordance with the IEEE 802.3 of/at Standard. For the PSE device to detect the MPS, the PD may periodically draw power of approximately 10 mA. If the PSE device does not detect at least a 10 mA current for a period of time, the PSE may disconnect power to the PD.